Diesel exhaust treatment apparatus

ABSTRACT

Apparatus for attenuating particulate matter and volatile organic compounds in exhaust gases of diesel engines. The apparatus includes a housing disposed serially relative to exhaust gas flow. The housing encloses mechanical filters having gas orifices of different sizes, and after the filters, a low temperature, low restriction catalytic converter. Pressure may be monitored to infer clogging by particulates. Clogging may be annunciated by an indicating light. Individual filters may be contained within plural separate filter canisters, which may be removed for cleaning. The housing may be substantially of aluminum, having cooling fins and a longitudinally oriented mounting foot. Filters may be arranged such that their orifices are misaligned to promote separation of particulates from the exhaust gases.

FIELD OF THE INVENTION

The present invention relates to treatment of exhaust of diesel engines, and more particularly to a filter for attenuating diesel particulate emissions as the emissions are produced.

BACKGROUND OF THE INVENTION

Diesel engines are subject to limitations on exhaust emissions as are gasoline engines, although the nature of diesel emissions differs from that of gasoline exhaust products. Under ideal conditions, diesel emissions are quite limited. However, under less than optimum conditions, diesel engines produce objectionable exhaust borne substances.

Some of the emitted substances are volatile organic compounds, which may result from high pressures in combination with relatively fuels of relatively complex hydrocarbon structure such as cetane. Other substances include particulate matter, popularly known as soot. Particulate matter is heavily carbonaceous, but may include volatile organic compounds, and is produced mostly when a diesel engine is lightly loaded. This is because under light loading, combustion chamber temperatures are sufficiently cool to the point that not all of the hydrocarbon fuel compounds burn to completion.

There exists a need to address diesel exhaust emissions of organic particulate matter and volatile organic compounds.

SUMMARY OF THE INVENTION

The present invention provides apparatus for trapping and attenuating organic particulate matter or both particulate matter and volatile organic compounds, in diesel exhaust gases. The apparatus may comprise a random series of filters or screens of different orifice size, which may operate in conjunction with a catalyst. For example, the series of filers or screens can have progressively smaller orifice size. The filters and catalyst, where the latter is used, may be contained within a housing adapted to transfer exhaust heat to ambient air, thereby lowering exhaust temperatures and promoting precipitation of gas borne particulates. The catalyst may be a low temperature, low restriction catalyst. The housing, together with the filters and catalyst, may be installed in series within the exhaust system of a diesel engine. Pressure sensors may be used to sense impending clogging of the filters, at which point the apparatus may be serviced by disassembling and cleaning, then reinstalled. An alarm such as an indicating light may be illuminated to alert the operator of the diesel powered equipment that clogging has occurred.

It is an object of the invention to provide apparatus for separating and trapping particulate material from diesel exhaust gases.

It is an object of the invention to provide improved elements and arrangements thereof by apparatus for the purposes described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes.

These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:

FIG. 1 is a side view of an apparatus for attenuating particulate matter in the exhaust of a diesel engine, according to at least one aspect of the invention.

FIG. 2 is a perspective view of the housing of the apparatus of FIG. 1.

FIG. 3 is an end view of the housing of FIG. 2, but also showing a mechanical baffle or filter.

FIG. 4 is an exploded perspective view of the housing of FIG. 2, but also showing internal components of the housing.

FIG. 5 is a diagrammatic representation of exhaust gas passage orifice sizes and an order in which they could be arrayed in the apparatus of FIG. 1.

FIG. 6 is an enlarged perspective detail view showing misalignment of exhaust gas passage orifices.

FIG. 7 is a diagrammatic side view of an apparatus for attenuating particulate matter in the exhaust of a diesel engine, according to at least one further aspect of the invention.

FIG. 8 is a diagrammatic side view similar to FIG. 7, showing a still further aspect of the invention.

FIG. 9 is a diagrammatic side view of an apparatus for attenuating particulate matter in the exhaust of a diesel engine, according to yet another aspect of the invention.

FIG. 10 is a diagrammatic representation of mechanical baffles or filters separated by metallic spacer rings.

DETAILED DESCRIPTION

Referring first to FIG. 1, according to at least one aspect of the invention, there is shown an apparatus 100 for attenuating particulate matter in the exhaust of a diesel engine (not shown). Where used as a noun, “exhaust” implies a mixture comprising primarily gases, possibly with liquids either liquid form entrained therein or in gaseous form or both, and also possibly with solid particulate matter which is borne in the gases. The apparatus 10 is to be installed in series with the flow of exhaust gases, and upon casual inspection may appear similar to a muffler, resonator, or in-line catalytic converter of a conventional automotive exhaust system (not shown). The apparatus 100 may comprise a housing 102 having a circumferential wall 104 extending along the length of the housing 102, a longitudinal axis 105, an inlet end 106, and an outlet end 108. For purposes of description, the inlet end 106 is located at the left in FIG. 1, and is that end which receives incoming exhaust gases which flow in the direction indicated by an arrow 110. Correspondingly, the exhaust gases exit the apparatus 10 as indicated by an arrow 112 located proximate the outlet end 108. The inlet end 106 and the outlet end 108 may each comprise respective conical sections 114, 116, and annular stub ends 118, 120. The circumferential wall 104 is seen to bear a plurality of external cooling fins 122, 124, 126, 128, 130.

Referring also to FIG. 2, the housing 102 is also seen to comprise a mounting flange 132 extending in the longitudinal direction. That is, the length of the mounting flange 132 is aligned with the length of the mounting flange 132. The mounting flange 132 may have a flat bottom surface 134 which faces away from the circumferential wall 104, thereby presenting a planar surface which could be exploited for example to stably seat the apparatus 100 against a flat surface of a vehicle or equipment (neither shown) having a diesel engine. The flat bottom surface 134 is advantageous since the general configuration of the housing is mostly cylindrical. The mounting flange 132 may also comprise a first projecting member 136 and an opposed second projecting member 138 which are generally tangential to the housing 102. The projecting members 136, 138 could be utilized to mount the apparatus 100 to a cooperatively shaped bracket (not shown) for example.

It will also be seen that the cooling fins 122, 124, 126, 128, 130 may have counterparts on the opposed side of the housing 102 in the form of cooling fins 140, 142, 144, 146, 148.

Turning now to FIG. 3, particulate matter is separated from the exhaust gases at least in part by a plurality of mechanical baffles or filters (only one mechanical filter 150 being visible in FIG. 3). Each mechanical filter 150 may comprise an aluminum or other metallic plate bearing a great many exhaust gas passage orifices 152. As employed herein, the term “aluminum” encompasses any metallic composition which is substantially aluminum, and includes alloys comprising mostly aluminum. Also referring to FIG. 4, mechanical filters 150 may be arranged in serial, spaced apart relation within filter canisters 154, 156, 158, 160. The filter canisters 154, 156, 158, 160 which may also comprise aluminum or other metallic constituency, are arranged serially within the chamber 162 defined by the open interior of the housing 102. There may be for example four filter canisters 154, 156, 158, 160 contained within the housing 102, each filter canister 154, 156, 158 or 160 containing a plurality of mechanical filters 150. Metallic spacer rings 164 may be provided to separate and space apart adjacent mechanical filters 150. Alternative to using rings 164, the filter can have a footing about its perimeter.

As shown diagrammatically in FIG. 5, exhaust gas passage orifices 152 may be of different sizes, such as differing in diameter. Within each one of the filter canisters 154, 156, 158, 160, the mechanical filters 150 contained therein are arranged in a random order. For example, the series can include an order such that no exhaust gas passage orifice 150 is of greater orifice size than that of any exhaust gas passage orifice 150 which is closer to the inlet end 106 of the housing 102. Alternatively stated, and as shown in FIG. 5, within each one of the filter canisters 154, 156, 158, 160 exhaust gas passage orifices 150 are arrayed in order of relatively large to relatively small sizes starting at that end of each filter canister 154, 156, 158 or 160 which is closer to the inlet end 106, and proceeding towards that end of each filter canister 154, 156, 158 or 160 which is closer to the outlet end 108. This pattern of progressively decreasing orifice size, seen in FIG. 5 as orifices 166, 168, 170, 172, which collectively provide four progressively smaller sizes, considered starting from the left, may be repeated after the first filter canister 154 in each and every succeeding filter canister such as the filter canisters 156, 158, 160. This does not necessarily imply that the exhaust gas passage orifices 150 of every succeeding mechanical filter 150 be smaller in size than those of a predecessor mechanical filter 150 closer to the inlet end 106. It would be possible for example to provide in series two mechanical filters 150 having the same exhaust gas passage orifice size before making the transition to a mechanical filter 150 having an exhaust gas passage orifice 152 of a different size.

It should be noted at this point that orientational terms such as predecessor refer to the direction of flow of exhaust gases through the device in normal use. As illustrated in FIG. 1, the flow of exhaust gases if from left to right.

As seen in FIG. 6, adjacent mechanical filters 150 may be staggered or otherwise arranged to assure that an exhaust gas passage orifice 152 of any one of the mechanical filters 150 is out of linear registry with the exhaust gas passage orifices 152 of an adjacent mechanical filter 150. In FIG. 6, it is seen that the center line 174 of one exhaust gas passage orifice 152, when extended, intercepts the solid wall of the adjacent mechanical filter 150, and is not in registry or alignment with the exhaust gas passage orifices 152 of the adjacent mechanical filter 150.

The housing 102 may be of aluminum in whole or in part. Because of metal consitutuency and of close fit, the relation of the mechanical filters 150, the filter canisters 154, 156, 158, 160, and the housing 102 is such that all of these are disposed in heat transfer relation to one another.

The inlet end 106 of the housing 102 transfers exhaust heat to ambient air. As seen in FIG. 1, the interior 176 as well as the outer surface 178 of the inlet end 106 are conical. As employed herein, the term “conical” will be understood to encompass frustoconical. This sudden widening of the gas passage defined within the interior 176 of the inlet end 106 may promote precipitation or other separation of particulate matter from the exhaust. It is possible that liquids such as water and volatile organic compounds such as chlorobenzene are removed from the more carbonaceous particulates by being boiled off, thereby enabling entrapment of particulate matter either within the inlet end 106 or in the interstitial spaces separating adjacent mechanical filters 150. It may also be that the frustoconical interior of the inlet end 106 promotes vortex flow of exhaust therein. Therefore, the conical configuration and open interior of the inlet end 106 may cause at least some separation of particulate matter from exhaust flowing through the apparatus 100 occurs at the inlet end 106 of the housing 102.

The apparatus 100 may comprise a pressure sensing arrangement which may be used to determine by inference whether the apparatus 100 has become clogged by particulate matter which has been separated from the exhaust gases. This may be implemented in several ways. As seen in FIG. 7, determination of clogging by the pressure sensing arrangement may utilize a pressure sensor 180 mounted to the inlet end 106, and is based on a threshold of a single predetermined pressure value being exceeded within the opening 176 of the inlet end 106. For example, in a typical diesel powered vehicle (not shown), should exhaust pressures exceed thirty-five pounds per square inch, it may be inferred that exhaust pressure is increasing due to filter clogging. Responsively to exceeding the predetermined pressure value, an alarm such as an indicating light 182 may be illuminated.

In another implementation seen in FIG. 8, determination of clogging by the pressure sensing arrangement utilizes a first pressure sensor 184 disposed to sense exhaust gas pressures proximate or at the inlet end 106 and a second pressure sensor 186 disposed to sense exhaust gas pressures proximate or at the outlet end 108. In the arrangement of FIG. 8, determination of clogging by the pressure sensing arrangement is based on a threshold of a differential in pressures sensed by the first pressure sensor 184 and the second pressure sensor 186 being exceeded. Responsively to determining clogging, an alarm such as an indicating light 188 may be illuminated. Signals from the first pressure sensor 184 and the second pressure sensor 186 may be processed by a processor 190 in order to generate a signal to operate the indicating lamp 188.

Referring again to FIG. 4, the apparatus 100 may comprise a catalytic converter 192 disposed serially within the housing 102 on that side of the mechanical filters 150 which is proximate the outlet end 108 (see FIG. 1). The catalytic converter 192 may be for example, a low temperature, low restriction catalytic converter having characteristics of the type sold by the Camet Company of the Davison Division of W. R. Grace, Inc., and which is in use for example in electrical power generating facilities.

FIG. 9 shows a variation on the arrangement of FIG. 1, which variation may include the functional features of the arrangement of FIG. 1. In FIG. 9, there is shown an apparatus 200 comprising a first section 202 and a second section 204. The first section 202 may contain and enclose filter canisters and mechanical filters such as the filter canisters 154, 156, 158, 160, the mechanical filters 150, and spacer rings such as the spacer rings 164. The second section 204 may contain and enclose a catalytic converter (not visible, but corresponding to the catalytic converter 192 of FIG. 4). A connecting conduit 206 may connect the first section 202 to the second section 204. It will be seen that the first section 202 has a first diameter 208, the second section 204 has a second diameter 210, and the connecting conduit 206 has a third diameter 212 which is less in magnitude than the first diameter 208 and the second diameter 210. This construction would result for example where the catalytic converter 192 is purchased commercially with its own housing 214, and need only be connected to the first section 202 by for example welding a section of pipe between the two sections 202, 204.

Although the invention has been described in terms of certain components being referred to in either the singular or the plural, other arrangements are possible. For example, it is to be understood that due to the conceptual description presented herein, components presented in the singular may be provided in the plural. Illustratively, the catalytic converter may be provided in plural segments or plural catalytic converter assemblies (this option is not shown).

The present invention is susceptible to modifications and variations which may be introduced thereto without departing from the inventive concepts. For example, exhaust gas passage orifices 152 of individual mechanical filters 150 may vary in configuration, orientation, and in other ways. Also, a housing corresponding to the housing 102 may vary in cross sectional configuration, being rectangular, oblong, irregular in cross section, for example. The frustoconical configuration of the inlet end 106 and the outlet end 108 could be belled or otherwise curved or varied.

The number, size, and arrangement of cooling fins such as the cooling fins 122, 124, 126, 128, 130, 140, 142, 144, 146, 148 may be varied as desired.

The mounting flange 132 may be drilled to accept threaded fasteners if desired (this option is not shown).

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is to be understood that the present invention is not to be limited to the disclosed arrangements, but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible. 

1. Apparatus for attenuating particulate matter in the exhaust of a diesel engine, comprising: a housing having a circumferential wall, a longitudinal axis, an inlet end, and an outlet end; and a plurality of filter canisters each containing mechanical filters having exhaust gas passage orifices, disposed serially within the housing, and wherein the exhaust gas passage orifices of the mechanical filters are of at least two different orifice sizes.
 2. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein within each one of the filter canisters, the mechanical filters contained therein are arranged in a random order.
 3. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the mechanical filters contained within each said filter canister are spaced apart from one another.
 4. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the exhaust gas passage orifices of any one of the mechanical filters are out of linear registry with the exhaust gas passage orifices of an adjacent mechanical filter.
 5. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the housing comprises a metallic composition substantially of aluminum.
 6. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the filter canisters and the mechanical filters are metallic and are disposed in heat transfer relation to the housing.
 7. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the housing comprises a plurality of external cooling fins.
 8. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the housing has conical configuration and an open interior at the inlet end, whereby at least some separation of particulate matter from exhaust flowing through the apparatus occurs at the inlet end of the housing.
 9. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the housing comprises a mounting flange extending in the longitudinal direction.
 10. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the housing is cylindrical and the mounting flange presents a planar surface away from the housing, and the mounting flange is generally tangential to the housing.
 11. The apparatus for attenuating particulate matter and in the exhaust of a diesel engine of claim 1, further comprising a pressure sensing arrangement which may be used to determine by inference whether the apparatus for attenuating particulate matter and volatile organic compounds in the exhaust of a diesel engine has become clogged by particulate matter which has been separated from the exhaust gases.
 12. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 11, wherein determination of clogging by the pressure sensing arrangement utilizes one pressure sensor, and is based on a threshold of a single predetermined pressure value being exceeded.
 13. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 11, wherein determination of clogging by the pressure sensing arrangement utilizes a first pressure sensor disposed to sense exhaust gas pressures proximate the inlet end and a second pressure sensor disposed to sense exhaust gas pressures proximate the outlet end, and wherein determination of clogging by the pressure sensing arrangement is based on a threshold of a differential in pressures sensed by the first pressure sensor and the second pressure sensor being exceeded.
 14. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 11, further comprising an alarm arrangement which is disposed to signal an alarm condition responsive to determining that the filter is clogged.
 15. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 11, wherein the alarm arrangement comprises an indicating light.
 16. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, further comprising a catalytic converter disposed serially within the housing on that side of the mechanical filters which is proximate the outlet end.
 17. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 16, wherein the catalytic converter is a low temperature, low restriction type.
 18. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 16, wherein the housing comprises a first section enclosing the filter canisters, a second section enclosing the catalytic converter, and a connecting conduit disposed to connect the first section to the second section, wherein the first section has a first diameter, the second section has a second diameter, and the connecting conduit has a third diameter which is less in magnitude than the first diameter and the second diameter.
 19. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the number of filter canisters containing mechanical filters is four.
 20. The apparatus for attenuating particulate matter in the exhaust of a diesel engine of claim 1, wherein the exhaust gas passage orifices of the mechanical filters are of four different orifice sizes. 